When printing is performed using an ink jet printer, an image output as a print result may have an uneven density distribution with streaks and unevenness due to, for example, the characteristics of the nozzles for ejecting ink droplets. As such, conventional technologies which adjust ink droplet volume in order to prevent the occurrence of streaks and unevenness are known. For example, a known apparatus generates correction data on the basis of a density distribution of a print result of a test pattern and adjusts the volume of the ink droplets for image printing on the basis of the correction data.